1. Field of the Invention
This invention relates to a heat exchanger including two kinds of tubes joined to each other for performing heat-exchange between fluids respectively flowing in the tubes, and to a method for manufacturing the same.
2. Description of the Related Art
JP-A-5-196377 proposes a heat exchanger including two flat tubes that respectively have plural fluid passages therein and are thermally joined to each other by brazing or soldering at an entire region in a longitudinal direction thereof. In this heat exchanger, heat is transmitted from fluid (for instance; refrigerant) flowing in one of the tubes to fluid (for instance, water) flowing in the other one of the tubes.
An object of the present invention is to provide a heat exchanger including two tubes for exchanging heat between fluids flowing therein with high heat exchanging efficiency.
According to one aspect of the present invention, a heat exchanger has a first tube defining therein a first fluid passage in which first fluid flows, and a second tube contacting the first tube and defining therein a second fluid passage in which second fluid flows. The first tube has a first joint surface brazed to a second joint surface of the second tube. A groove is provided on the first joint surface to divide the first joint surface into at least two regions such that the first joint surface is brazed to the second joint surface at the regions other than the groove. Accordingly, the first joint surface and the second joint surface can be brazed to each other uniformly without producing large voids therebetween. This prevents deterioration of heat exchanging efficiency of the heat exchanger.
According to another aspect of the present invention, a first tube is composed of a plurality of first tube bodies that are disposed in parallel with each other such that first fluid flows in the plurality of first tube bodies with a serpentine path, and such that the first fluid flows in each of the plurality of first tube bodies in a first fluid direction approximately perpendicular to a second fluid direction in which second fluid flows a second tube.
Preferably, the plurality of first tube bodies are arranged in a direction perpendicular to a longitudinal direction thereof and perpendicular to a longitudinal direction of the second tube. Preferably, the second tube meanders to extend in the direction in which the plurality of first tube bodies are arranged and to have a plurality of second tube portions each extending in the second fluid direction such that the second fluid flows in each of the plurality of second tube portions in the second fluid direction to form a serpentine path.
Accordingly, the first fluid flowing in the first tube and the second fluid flowing in the second tube can exchange heat therebetween effectively. Further, the heat exchanger can be provided with a compact size.